Hui Wang

Dechlorane Plus (DP) is an emerging persistent organic pollutants, yet few studies have been conducted in China, especially in urban dust. DP was measured and detected in urban street dust samples collected from Shenyang City, China. Spatial distribution, potential sources, and health risks of DP in urban dust were assessed in this study. Results show that anti-DP was easier to detect than syn-DP due to the proportion of DP production, stability, migration capability, and physical and chemical properties of DP isomers. Mean ∑DP, syn-DP, and anti-DP concentrations were 25.95 ± 11.59 ng/g, 5.71 ± 3.78 ng/g, and 21.57 ± 9.19 ng/g, respectively. Results suggested that levels of DP pollution were influenced by land-use type, and differences in DP between the two major transportation networks in the city (e.g., first-ring road and second-ring road) were not significant. Results of correlation analysis and fractional abundance of DP isomers were consistent, indicating that PD in urban dust of Shenyang City is mainly derived from commercial DP products. Although the health risks of DP in the dust of Shenyang City were within acceptable levels, results of exposure doses and health risks suggested that children were more susceptible to the impacts of DP than adults, with oral ingestion being a more important exposure pathway than dermal absorption.

Dechlorane Plus (DP), an emerging type of persistent organic pollutant (POP), poses potential harmful effects on plants, animals, and humans alike, garnering increasing attention. Urban surface soil is easily accessible to urban residents, and its environmental conditions have a more significant impact on urban residents. However, there are few studies on related DP contamination. In this study, the contamination of DP in surface soil from Shenyang City, Liaoning Province, China, was investigated. Soil samples were collected from 33 different locations in May and June 2023. The total DP (∑DP), anti-DP, and syn-DP were determined by gas chromatography and ranged from not detected (ND) to 77.80 ng/g, from ND to 61.50 ng/g, and from ND to 16.30 ng/g, respectively. The mean values were 33.60 ± 18.93 ng/g, 27.01 ± 14.32 ng/g, and 8.57 ± 4.55 ng/g. The findings indicate that anti-DP is more readily detectable than syn-DP, attributable to the lower proportion of syn-DP in the overall DP production and the distinct physicochemical properties of DP isomers. The fsyn [syn-DP/(anti-DP + syn-DP)] is 0.14–0.40, with a mean value of 0.22. This aligns closely with the values observed in commercial DP formulations, suggesting that the primary sources are derived from commercial DP products. Contour maps show that DP concentrations are influenced by urban land use and DP production. Based on the Tyson polygon method, the DP inventory was calculated at approximately 1.18 tons, with the unit area load exceeding previously reported values. The results also show that the health risks of DP are minimal, but children are more susceptible to the impacts of DP than adults, and oral ingestion is a more critical exposure pathway.

The heavy metal pollution in the surrounding environment of the Chaihe Pb-Zn Mine in Liaoning Province has become quite severe, yet our understanding of the chemical speciation and potential ecological risks of metals in the soil of its adjacent areas remains inadequate. Consequently, this study collected 28 soil samples from the vicinity of the Pb-Zn mine and analyzed the concentrations and speciation of Cr, As, Cu, Pb, Zn, Ni, and Cd in the soil. The results indicated that compared to background values, Cd was the metal with the highest level of exceedance, followed by Pb and Zn, with over-standard multiples of 62.33, 39.11, and 13.69, respectively. Notably, the average percentage of exchangeable Cd fractions reached 24.95%, suggesting a high bioavailability of this metal. This finding is echoed by the risk assessment code results, which indicated that Cd posed a high risk at 53.57% of the sampling sites and a medium risk at 39.29% of the sites. Furthermore, the risk index calculations revealed that the potential ecological risk in the study area was extremely severe, with cadmium and lead being the primary sources of risk. In conclusion, the contamination of Cd, Pb, and Zn in the soil surrounding the Chaihe Pb-Zn Mine is severe and requires urgent remediation measures.

Due to potassium persulfate’s excessive reaction speed and severe impact on the soil environment, slowing down the reaction rate and reducing its environmental impact is an important but challenging matter. Hence, microencapsulation technology was taken to modify potassium persulfate, and potassium persulfate microcapsules were used to remediate the PAHs-contaminated soil. The results of XRD and an infrared spectrum identified that the core material (potassium persulfate) exists after being encapsulated by the wall material (stearic acid), and there was no chemical reaction between the core material and wall material. The results of the sustained release effect and kinetic equation showed that the release rate of the potassium persulfate microcapsules was close to 60% after 48 h, and it had a good sustained-release effect compared with previous studies. The results of the radical probe revealed that the free radicals produced from potassium persulfate microcapsules activated by Fe²⁺ were the main reasons for the degradation of PAHs, and SO₄⁻· played the most important major role in the degradation of PAHs, followed by ·OH, and the reducing substances also played an auxiliary role. The results also suggested that potassium persulfate microcapsules not only degraded PAHs in soil (53.6% after 72 h) but also had fewer negative effects on the environment, and they even promoted the growth and development of microorganisms and increased the germination rate of seeds due to the slow-release effect of the microcapsules. This work reveals the degradation mechanism of potassium persulfate microcapsules and provides a new amendment of potassium persulfate in the remediation of PAHs-contaminated soil.

A novel bacterium, Arthrobacter globiformis DC-1, capable of degrading DDT as its sole carbon and energy source, was isolated from DDT-contaminated agricultural soil. The bacterium can degrade up to 76.3% of the DDT at a concentration of 10 mg/L in the mineral salt medium (MSM) within 1 day of incubation. The effects of various environmental conditions, such as the concentration of DDT, temperature, pH and additional carbon sources, on its growth and biodegrading capacity of DDT were investigated in the MSM. The A. globiformis DC-1 strain could efficiently grow and degrade DDT at a wide range of concentrations, with the maximum growth and degradation rate at 10 mg/LDDT, followed by inhibitory effects at higher concentrations (20 and 30 mg/LDDT). Mesophilic temperatures (25–30 °C) and a pH of 7–7.5 were the most suitable conditions for the growth and biodegradation. The presence of carbon sources significantly increased the growth of the DC-1 strain; however, degradation was inhibited in the present of glucose, sucrose and fructose, and peptone was determined to be the most appropriate carbon source for A. globiformis DC-1. The optimal DDT degradation (84.2%) was observed at 10 mg/LDDT, peptone as carbon source in pH 7.5 at 30 °C with 1 day of incubation. This strain could also degrade DDE, DDD and DDT simultaneously as the sole carbon and energy source, with degradation rates reaching 70.61%, 64.43% and 60.24% in 10 days, respectively. The biodegradation pathway by A. globiformis DC-1 revealed that DDT was converted to DDD and DDE via dechlorination and dehydrochlorination, respectively; subsequently, both DDD and DDE transformed to DDMU through further dechlorination, and finally, after ring opening, DDMU was mineralized to carbon dioxide. No intermediate metabolites accumulation was observed during the GC/MS analysis, demonstrating that the A. globiformis DC-1 strain can be used for the bioremediation of DDT residues in the environment.

Polycyclic aromatic hydrocarbon (PAH) contaminated agricultural soil is widespread globally. To develop a cost-effective remediation technique to effectively degrade PAH contaminated agricultural soil without disturbing crop production, an in-situ co-remediation of PAH contaminated agricultural soil using blood meal and celery was assessed in an agricultural greenhouse. Results showed PAH dissipation rates increased significantly in agricultural soil when co-remediated by blood meal and celery. Planting celery and addition of 5 g•kg⁻¹ blood meal removed 53.13% of PAHs within three months. Residual PAH concentrations in plant tissue were much lower than China Standard food limits. Results indicated the ability of celery to enhance bioavailability of PAHs, and create favorable conditions for microbial, rather than direct plant uptake, played a vital role in degradation of PAHs. Addition of blood meal significantly enhanced soil enzyme activity and PAH degradation, and increased PAH remediation rate with optimal addition of blood meal (5 g•kg⁻¹). Celery enhanced bioavailability of PAHs. Blood meal increased soil enzyme activity and increased PAH degrading bacterial activity, which acted as the main remediation pathway to co-remediate PAHs, where celery was safe to eat. Therefore, a novel in-situ agricultural soil PAH remedial method, which did not disturb normal agricultural production during remediation is presented in this study.

Concentrations, composition profiles, sources, and health risks of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in urban soils from 23 cities across China based on metadata collected from previous studies between 2005 and 2021 were investigated. ΣPAH concentrations in urban soils from 23 cities across China ranged from 0.1231 to 17.2000 mg/kg (mean = 2.7171 ± 3.8276 mg/kg). Overall PAH contamination in urban soils across China was moderate compared to that in global cities. Based on energy consumption and climate conditions, the spatial distributions of mean ΣPAH concentrations in Northeast China were highest, followed by those in North China, West China, East China, and South China. Individual PAH composition profiles decreased in the order: 4-ring PAHs (41.36%) > 5-ring PAHs (21.77%) > 3-ring PAHs (18.53%) > 6-ring PAHs (14.00%) > 2-ring PAHs (2.27%). Diagnostic ratios and positive matrix factorization (PMF) revealed that PAHs in urban soils were mainly derived from fossil fuel combustion (from coal, natural gas, and biomass), especially in North, Northeast, and East China, with smaller contributions from petrogenic sources. Health risk assessment results suggest that although there are potential cancer risks from PAHs, risks were acceptable. Toxic equivalent concentration (TEQ) and the corresponding oral cancer slope factor (CFS₀) contributed most to the uncertainty of total risks. This study will help develop strategies to reduce PAH risk management in urban soils in China.

Characteristics, profile composition, ecological and human health risk of polycyclic aromatic hydrocarbons in surface dust collected from Shenyang city, China, were investigated. Concentrations of 16 USEPA priority PAHs ranged between 371.57 and 3300.04 μg/kg (mean 1244.76 ± 715.25 μg/kg). Fluoranthene was the most abundant individual PAHs, followed by pyrene, and high molecular weight PAHs, more than three times of low molecular weight PAHs, were the predominant components. Profiles of PAHs showed that 4-ring PAHs were dominant, followed by 3-ring and 5-ring PAHs, and indicated that combustion sources accounted for the most PAHs. Results of diagnostic ratios and positive matrix factorization all suggested that pyrogenic sources were the most important source of PAHs in urban dust, followed by natural gas combustion and petrogenic sources, and traffic emissions would play an increasingly critical role with the increasing of vehicles. Health risk assessment suggested children were the most vulnerable to PAHs compared to adolescents and adults. Ingestion was the most important exposure pathway. The total lifetime cancer risk of 43.33% of sampling sites was higher than 10^–6, but the TLCR at all sites was much lower than the highest acceptable risk established by USEPA (10^–4).

This paper proposes a quantitative method to optimize the existing river monitoring network based on a modified approaching degree model, T test, and Euclidean distance. In this study, the Liaohe River located in Liaoning province, China, was taken as a research object. Samples were collected from 8 sampling sites throughout the monitoring network, and water quality parameters were analyzed every 2 months from January 2009 to December 2010. The results show that the average concentrations of the ammonia nitrogen (NH₄⁺-N) and chemical oxygen demand (COD) were beyond grade III of the Environmental Quality Standards for Surface Water of China (GB3838-2002), and they were the main water quality parameters. After optimization, the number of monitoring sections along the Liaohe River was reduced to five from the original eight, thus saving 37.5% of the monitoring cost; meanwhile, there is no significant difference between the un-optimized and optimized monitoring networks, and the optimized monitoring network remains to be able to perform as good as the original one. In addition, the total data attainment rate was improved greatly, and the duplicate setting degree of monitoring points decreased significantly compared with other optimal methods. The optimized monitoring network proves to be more efficient, reasonable, and economically feasible, so this quantitative method can help optimize the changing orderly river monitoring networks.

Polycyclic aromatic hydrocarbons (PAHs) occur in the surface water of the Taizi River, China. The levels and composition patterns were studied by high-performance liquid chromatography and PAHs sources were analyzed using the isomer ratios of selected PAH compounds. In the flood period, concentrations of PAHs ranged from 1562.52 to 4176.15 ng/L with a mean of 2562.56 ng/L. In the dry period, concentrations ranged from 498.09 to 3218.27 ng/L with a mean of 1389.30 ng/L. The levels of sigma PAHs in the study area were higher than in other locations. The dominant PAHs were Baa in the flood period and Phe, Flu and Pyr in the dry period. The composition of PAHs was dominated by four-ring PAHs (51.72-82.69%) in the flood period and three-ring (28.25-50.10%) and four-ring PAHs (38.28-56.28%) in the dry period. The isomer ratios of Ant/(Ant + Phe), Flu/(Flu + Pyr) and compositional analysis were selected to identify the sources of PAHs. Coal combustion and traffic emission were the sources of PAHs in the surface water of the Taizi River, and the major source of PAHs was from combustion of coal.